1. Field of the Invention
The present invention generally relates to audiovisual program distribution systems and, more particular, to switching a source of an audiovisual program configured for distribution among user terminals.
2. Description of the Related Art
Digital bitstream splicing is a process that replaces part of a bitstream with another bitstream. Typically, such a splicing operation has been used to insert an advertisement into a program stream of a network feed. In such an application, the program stream is a real-time feed from a distribution network (i.e., a live stream) and the advertisement is fetched from a storage medium (i.e., a stored stream). The insertion is typically short in duration, which allows the advertisement stream to be stored (e.g., one or two minutes in duration).
Historically, digital bitstream splicing operation has not been used to substitute a program stream from one live feed with a program feed from another live feed for a long-term or indefinite duration. Instead, such program substitution is achieved by switching uncompressed video and audio where the digital signals are decoded prior to switching and re-encoded after switching. This decoding/re-encoding process may deleteriously affect the digital signals by degrading the integrity of the data.
Accordingly, there exists a need in the art for a method and apparatus that switches a source of an audiovisual program configured for distribution among user terminals in the digital domain for long-term or indefinite periods.